Electrochemical devices, modules, and systems for hydrogen generation and methods of operating the same

Abstract

A system for hydrogen generation includes at least one cabinet defining a first volume, a second volume, and a third volume, wherein the first volume, the second volume, and the third volume are fluidly isolated from one another; a water circuit located within the first volume; an electrochemical module including an electrolyzer electrochemical stack located within the second volume; a hydrogen circuit located within the third volume; at least one first fluid connector fluidly connecting the water circuit and the electrolyzer electrochemical stack; and at least one second fluid connector fluidly connecting the electrolyzer electrochemical stack and the hydrogen circuit.

Description

Technical Field

[0001] (Cross - Reference to Related Applications) This application claims the benefit of U.S. Provisional Patent Application No. 62 / 938,494, filed on November 21, 2019, the entire content of which is incorporated herein by reference.

[0002] (Technical Field) The present disclosure generally relates to chemical production, and more specifically, to electrochemical modules and systems for hydrogen generation.

Background Art

[0003] Hydrogen is a common gas with many industrial applications such as petroleum refining, metal processing, food processing, and ammonia production. Hydrogen is abundant and can be formed from various renewable and non - renewable energy sources, but the flammability of hydrogen in air makes it difficult to store and transport hydrogen. As a result, hydrogen is generally not suitable for large - scale production in a unified facility for subsequent distribution across large geographical areas. Rather, hydrogen is generally used at or near its production facility.

Summary of the Invention

Means for Solving the Problems

[0004] According to one embodiment, a system for hydrogen generation includes at least one cabinet defining a first volume, a second volume, and a third volume, wherein the first volume, the second volume, and the third volume are fluidly isolated from each other; a water circuit located within the first volume; an electrochemical module including an electrolyzer electrochemical stack located within the second volume; a hydrogen circuit located within the third volume; at least one first fluid connector fluidly connecting the water circuit and the electrolyzer electrochemical stack; and at least one second fluid connector fluidly connecting the electrolyzer electrochemical stack and the hydrogen circuit.

[0005] In one embodiment, at least one cabinet comprises a single cabinet in which a first volume is separated from a second volume by a first inner wall, and the second volume is separated from a third volume by a second inner wall, and at least one first fluid connector extends through the first inner wall and at least one second fluid connector extends through the second inner wall.

[0006] In one embodiment, the system further comprises a first air mover configured to be fluidly connected to the first volume but not to the second or third volume and to ventilate the first volume without ventilating the second or third volume, a second air mover configured to be fluidly connected to the second volume but not to the first or third volume and to ventilate the second volume without ventilating the first or third volume, and a third air mover configured to be fluidly connected to the third volume but not to the first or second volume and to ventilate the third volume without ventilating the first or second volume.

[0007] In another embodiment, an electrochemical module for hydrogen treatment includes a liquid management section including a plurality of water connectors and at least one water manifold, and a gas management section located above the liquid management section and in fluid connection with the liquid management section, the gas management section including an electrolytic cell electrochemical stack and a hydrogen connector. The electrolytic cell electrochemical stack includes at least one bipolar plate and a plurality of membrane electrode assemblies (MEAs). At least one bipolar plate is sealingly engaged with one of the plurality of MEAs to define an anode channel therebetween, and at least one bipolar plate is sealingly engaged with another one of the plurality of MEAs to define a cathode channel therebetween. Each of the plurality of water connectors is in fluid communication with the anode channel via at least one manifold, and the hydrogen connector is in fluid communication with the cathode channel.

[0008] In another embodiment, a bipolar plate for an electrolytic cell electrochemical stack is a substrate having opposing anode and cathode sides, the substrate defining a plurality of anode ports and a plurality of cathode ports each extending from the anode side to the cathode side of the substrate, the anode side defining an anode flow field oriented to direct water between at least some of the plurality of anode ports, the cathode side defining a cathode flow field oriented to direct hydrogen gas toward the plurality of cathode ports, a substrate; an anode gasket surrounding the anode flow field and the plurality of anode ports along the anode side of the substrate, the plurality of cathode ports being located outside the anode gasket; and a cathode gasket surrounding the cathode flow field, the plurality of anode ports, and the plurality of cathode ports along the cathode side of the substrate.

[0009] In another embodiment, a hydrogen generation method includes electrolyzing water in an electrolytic cell to generate a wet hydrogen stream, drying the wet hydrogen stream in a dryer to generate a dry hydrogen stream and a water and hydrogen-containing stream, and providing the water and hydrogen-containing stream to a hydrogen pump to pump hydrogen from the water and hydrogen-containing stream into the dryer.

[0010] In one embodiment, the method also includes providing a water and oxygen-containing stream from the electrolytic cell to a separator, separating water from oxygen in the water and oxygen-containing stream in the separator, and providing the separated water into the electrolytic cell. The present invention provides, for example, the following. (Item 1) A system for hydrogen generation, at least one cabinet defining a first volume, a second volume, and a third volume, wherein the first volume, the second volume, and the third volume are fluidly isolated from each other, at least one cabinet; a water circuit located within the first volume; an electrochemical module comprising an electrolytic cell electrochemical stack located within the second volume; a hydrogen circuit located within the third volume; at least one first fluid connector fluidly connecting the water circuit and the electrolytic cell electrochemical stack; and at least one second fluid connector fluidly connecting the electrolytic cell electrochemical stack and the hydrogen circuit A system comprising. (Item 2) The at least one cabinet comprises a single cabinet, within which the first volume is isolated from the second volume by a first inner wall, and the second volume is isolated from the third volume by a second inner wall. The at least one first fluid connector extends through the first inner wall. The at least one second fluid connector extends through the second inner wall. The system according to Item 1. (Item 3) A first air mover, wherein the first air mover is fluidly connected to the first volume but not to the second or third volume, and is configured to ventilate the first volume without ventilating the second or third volume. A second air mover, wherein the second air mover is fluidly connected to the second volume but not to the first or third volume, and is configured to ventilate the second volume without ventilating the first or third volume. A third air mover, wherein the third air mover is fluidly connected to the third volume but not to the first or second volume, and is configured to ventilate the third volume without ventilating the first or second volume. The system according to Item 1, further comprising. (Item 4) The system of item 3, wherein the first, second, and third gas movers are operable to form an individual negative pressure within each of the first volume, the second volume, and the third volume with respect to the environment outside the single cabinet. (Item 5) The electrolytic cell electrochemical stack includes at least one bipolar plate and a plurality of membrane electrode assemblies (MEAs). The plurality of MEAs and the at least one bipolar plate define at least one anode channel and at least one cathode channel separated from each other by the at least one bipolar plate. The at least one anode channel is in fluid communication with the water circuit via the at least one first fluid connector. The at least one cathode channel is in fluid communication with the hydrogen circuit via the second fluid connector. The MEA includes an anode, a cathode, and a proton exchange membrane therebetween. The second volume is located between the first volume and the third volume. The system of item 1. (Item 6) The water circuit includes a pump, a reservoir, and a separator. The at least one first fluid connector includes two fluid connectors. The reservoir is in fluid communication between the separator and the pump. The pump is in fluid communication with the anode channel of the electrochemical stack via one of the two first fluid connectors. The separator is in fluid communication with at least one anode channel of the electrochemical stack via the second of the two first fluid connectors. The system of item 5. (Item 7) The hydrogen circuit includes a dryer having an inlet portion in fluid communication with at least one cathode channel of the electrolytic cell electrochemical stack via the second fluid connector, and a hydrogen pump in fluid communication with the outlet portion and the inlet portion of the dryer, the hydrogen pump being operable to recirculate pressurized hydrogen from the outlet portion of the dryer to the inlet portion of the dryer. The system of item 5 comprising the above. (Item 8) A controller, wherein the controller is in electrical communication with the electrochemical stack and is located within a fourth volume of the cabinet that is fluidly isolated from each of the first volume, the second volume, and the third volume. An electrical contact disposed on an outer surface of the at least one cabinet, wherein the electrical contact is releasably engageable while in electrical communication with a power source, and the electrical contact is in electrical communication with the electrochemical stack via the controller. An electrical contact The system according to item 4, further comprising. (Item 9) The system according to item 8, further comprising a fan in fluid communication with the fourth volume, the fan being operable to create a positive pressure within the fourth volume with respect to the environment outside the cabinet. (Item 10) Further comprising a plurality of gas sensors, each of the plurality of gas sensors being configured to measure a hydrogen-containing gas, each gas sensor being disposed within an individual one of the first volume, the second volume, and the third volume, each gas sensor being in electrical communication with the controller, and the controller being configured to interrupt electrical communication between the power source and the equipment within the cabinet based on a signal received from one or more of the plurality of gas sensors. The system according to item 8. (Item 11) An electrochemical module for hydrogen treatment, comprising a liquid management section including a plurality of water connectors and at least one water manifold, a gas management section, the gas management section being located above the liquid management section and fluidly connected to the liquid management section, and including an electrolytic cell electrochemical stack and a hydrogen connector, the electrolytic cell electrochemical stack including at least one bipolar plate and a plurality of membrane electrode assemblies (MEAs), the at least one bipolar plate being sealingly engaged with one of the plurality of MEAs and defining an anode channel therebetween, the at least one bipolar plate being sealingly engaged with another one of the plurality of MEAs and defining a cathode channel therebetween, each of the plurality of water connectors being in fluid communication with the anode channel via the at least one manifold, and the hydrogen connector being in fluid communication with the cathode channel. A gas management section An electrochemical module comprising. (Item 12) Each of the plurality of water connectors and the at least one manifold of the liquid management section is releasably fixable while being in fluid communication with the anode channels of the electrochemical stack of the gas management section, The liquid management section and the gas management section are removable from each other along the interface between the manifold and the electrochemical stack. The electrochemical module according to item 11. (Item 13) A bipolar plate for an electrolytic cell electrochemical stack, A substrate having mutually opposite anode and cathode sides, the substrate defining a plurality of anode ports and a plurality of cathode ports each extending from the anode side to the cathode side of the substrate, the anode side defining an anode flow field oriented to direct water between at least some of the plurality of anode ports, the cathode side defining a cathode flow field oriented to direct hydrogen gas toward the plurality of cathode ports, a substrate; An anode gasket surrounding the anode flow field and the plurality of anode ports along the anode side of the substrate, the plurality of cathode ports being located outside the anode gasket, an anode gasket; A cathode gasket surrounding the cathode flow field, the plurality of anode ports, and the plurality of cathode ports along the cathode side of the substrate A bipolar plate comprising. (Item 14) A cathode ring seal located on the anode side of the substrate and surrounding an individual cathode port, An anode ring seal located on the cathode side of the substrate and surrounding an individual anode port The bipolar plate according to item 13, further comprising. (Item 15) The anode gasket and the cathode gasket each have a different shape along the anode side and the cathode side of the substrate, The anode flow field and the cathode flow field each have the same shape along the anode side and the cathode side of the substrate. The bipolar plate according to item 14. (Item 16) The cathode flow field has a minimum bounding rectangle, The plurality of cathode ports comprise two cathode portions located diagonally opposite each other with respect to the minimum bounding rectangle. The anode gasket extends between the plurality of anode ports and the plurality of cathode ports on the anode side of the substrate. The bipolar plate according to item 14. (Item 17) The substrate is formed at least in part from one or more than one of plasticized graphite or carbon composite material. The anode side of the substrate contains an oxidation inhibitor that is conductive. The bipolar plate according to item 13. (Item 18) An electrochemical stack for hydrogen treatment, The bipolar plate according to item 14, A plurality of electrolytic cell membrane electrode assemblies (MEA), each MEA including an anode, a cathode, and a proton exchange membrane therebetween, a plurality of MEAs comprising One anode of the plurality of MEAs is sealingly engaged with the anode side of the substrate through the anode gasket such that anode channels are defined therebetween. Another cathode of the plurality of MEAs is sealingly engaged with the cathode side of the substrate through the cathode gasket such that cathode channels are defined therebetween. Electrochemical stack. (Item 19) A porous material disposed in an anode channel between one anode of the plurality of MEAs and the anode side of the substrate of the bipolar plate, A housing disposed around the plurality of MEAs and the bipolar plate, the housing including one or more than one of metal or aramid fiber, a housing further comprising the electrochemical stack according to item 18. (Item 20) A method for hydrogen generation, Electrolyzing water in an electrolytic cell to generate a wet hydrogen stream, Drying the wet hydrogen stream in a dryer to generate a dry hydrogen stream and a water and hydrogen-containing stream, Providing the water and hydrogen-containing stream to a hydrogen pump and pumping hydrogen from the water and hydrogen-containing stream into the dryer comprising a method. (Item 21) Providing a water and oxygen-containing stream from the electrolytic cell to a separator, Separating the water from the oxygen in the water and oxygen-containing stream in the separator, Providing the separated water into the electrolytic cell further comprising the method according to item 20.

Brief Description of the Drawings

[0011]

Figure 1A

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Figure 1B

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Figure 2A

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Figure 2B

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Figure 2C

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Figure 3A

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Figure 3B

[0018] Like reference symbols in the various drawings indicate like elements.

DETAILED DESCRIPTION OF THE INVENTION

[0019] Detailed Description The embodiments will now be described more fully with reference to the accompanying drawings, in which exemplary embodiments are shown. However, the foregoing may be embodied in many different forms and should not be construed as limited to the exemplary embodiments set forth herein. All fluid flows may flow through conduits (e.g., pipes and / or manifolds) unless otherwise defined.

[0020] All documents mentioned herein are hereby incorporated by reference in their entirety. References to items in the singular are to be construed to include the items in the plural unless otherwise explicitly stated or clear from the context, and vice versa. Grammatical connectives are intended to represent all disjunctive and conjunctive combinations of clauses, sentences, words, and the like that are joined by them unless otherwise stated or clear from the context. Accordingly, the term "or" is generally to be understood to mean "and / or," and the term "and" is also generally to be understood to mean "and / or."

[0021] The recitation of ranges of values herein is not intended to be limiting; rather, each individual value within the range is to be considered as separately incorporated herein as if it were individually recited herein, unless otherwise indicated herein. The words "about," "approximately," or the like, when accompanying a numerical value, are to be construed to include any deviation that would be understood by one of ordinary skill in the art for the intended purpose for which the value is being used. Values and / or ranges of values are provided herein only as examples and do not constitute a limitation on the scope of the described embodiments. The use of any example or illustrative language (e.g., "for example," "etc.," or the like) is merely intended to make the embodiments more apparent and does not impose a limitation on the scope of the embodiments. No language in this specification should be construed as indicating any non-claimed element as essential to the practice of the disclosed embodiments.

[0022] Installing the hydrogen production location at the same location as its final industrial use destination can present its own challenges related to factory footprint, safety, and resource availability. Therefore, there remains a need for hydrogen generation that can be cost-effectively implemented within a small footprint factory that is adaptable for safe implementation in a wide range of locations, including resource-constrained areas. In the following description, various aspects of the electrochemical devices, modules, and systems are described in the context of the electrochemical electrolysis of hydrogen and electricity from water, using separately ventilated cabinet sections (i.e., spaces) for electrolysis (i.e., the electrolyzer stack location), oxygen treatment, and hydrogen treatment. This configuration increases the safety of the system by separating the oxygen and hydrogen processing equipment into separately ventilated spaces and reducing the likelihood of mixing and exothermic reactions between the leaked oxygen and hydrogen.

[0023] Unless otherwise specified or clear from the context, any one or more of the various different devices, modules, or systems described herein may additionally or alternatively be used in any one or more of the various different electrochemical processes where a lower pressure reactant is an input to an electrochemical process that produces a higher pressure product. For example, unless the contrary intention is indicated, any one or more of the various different devices, modules, and systems described herein may be used to electrochemically pump hydrogen such that it may be useful for recirculating hydrogen and increasing the overall yield of a chemical process. As a more specific example, any one or more of the various different devices, modules, and systems described herein may be used to generate hydrogen for ammonia synthesis and / or recirculate hydrogen as part of any one or more of the various systems and methods described in a U.S. patent application to Ballantine, et al., filed on the same day as this document, having Attorney Docket No. 35055-001US, and entitled "SYSTEMS AND METHODS OF AMMONIA SYNTHESIS" (the entire contents of each of these references are incorporated herein by reference).

[0024] Referring now to FIGS. 1A and 1B, a system 100 for generating hydrogen may include an electrochemical module 102 and at least one cabinet 104. The at least one cabinet 104 may define a first volume 106a, a second volume 106b, and a third volume 106c, respectively, isolated from each other except for fluid connections between the electrochemical module 102 in the second volume 106b and equipment in the first volume 106a and the third volume 106c. One cabinet (i.e., housing) 104 with three isolated volumes (106a, 106b, 106c) is shown in FIG. 1A, but note that two or three separate cabinets 104, each containing one or two of the three isolated volumes, may be used instead. When a single cabinet 104 is used, adjacent isolated volumes are isolated from each other by the inner wall or partitions 105a, 105b of the cabinet 104. For example, the first inner wall 105a may separate the first volume 106a from the second volume 106b, and the second inner wall 105b may separate the second volume 106b from the third volume 106c. As used herein, two volumes are isolated from each other if the gas in one volume cannot pass into the other volume except through a designated fluid conduit (e.g., a pipe or manifold) configured to connect the two volumes and provide gas or liquid between the two volumes. In one embodiment, volumes 106a, 106b, and 106c are each separately ventilated by separate dedicated ventilation equipment, as will be described in further detail below.

[0025] The electrochemical module 102 may include an electrolytic cell module such as a proton exchange membrane (PEM)-based electrolytic cell module. The module 102 may include one or more electrochemical stacks 200 such as one or more PEM-based electrolytic cell stacks. The module 102 may also include a plurality of first fluid connectors 110a, b (collectively, the plurality of first fluid connectors 110a, b, individually, the first fluid connector 110a and the first fluid connector 110b) and a second fluid connector 112. As will be described in more detail below, the electrochemical module 102 is disposed within a second volume 106b (e.g., between the first volume 106a and the third volume 106c) and is fluidly connected to a water circuit 114 within the first volume 106a via the plurality of first fluid connectors 110a, b and to a hydrogen circuit 116 within the third volume 106c via the second fluid connector 112. Such partitioning of the electrochemical module 102, the water circuit (including oxygen treatment equipment) 114, and the hydrogen circuit 116 into individual volumes 106b, 106a, 106c that are isolated from each other within one or more cabinets 104 may facilitate the safe generation of commercial-scale amounts of hydrogen within a spatially compact footprint. This may be useful, inter alia, for generating hydrogen at a deployment location with limited space and / or for transporting the system 100 to a remote deployment facility using the system 100. Additionally or alternatively, and as will be described in more detail below, the connectivity between the electrochemical module 102 and each of the water circuit 114 and the hydrogen circuit 116 within the cabinet 104 may include modularity that facilitates deployment, maintenance, and repair.

[0026] In use, as described in more detail below, water and electricity may be provided to the electrochemical stack 200, and a portion of the water may be electrochemically electrolyzed to form hydrogen (e.g., via hydrogen ion diffusion, through the PEM electrolyte, from the anode side of the electrolytic cell to the cathode side of the PEM electrolytic cell). For example, the water circuit 114 may be operable to deliver purified water from the first volume 106a of the cabinet 104 to the electrochemical stack 200 within the second volume 106b of the cabinet 104 via a first fluid coupling. As the purified water moves through the electrochemical stack 200, the electrical power delivered to the electrochemical stack 200 may move protons of at least a portion of the purified water through the PEM electrolyte to form hydrogen. Oxygen formed on the anode side of the cell by electrolysis of the purified water may be returned from the electrochemical stack 200 within the second volume 106b to the water circuit 114 within the first volume 106a, along with the over-purified water. Additionally, or alternatively, hydrogen formed by electrolysis within the electrochemical stack 200 may move from the cathode side of the electrochemical stack 200 within the second volume 106b of the cabinet 104 to the hydrogen circuit 116 within the third volume 106c of the cabinet 104. Thus, as long as oxygen and hydrogen are present within the second volume 106b, the electrochemical stack 200 manages these flows separately, directs these flows to different portions (i.e., isolated volumes) of the cabinet 104, and reduces the likelihood of inadvertent mixing of oxygen and hydrogen that forms a flammable mixture, as compared to a configuration where oxygen and hydrogen are processed within the same enclosed volume.

[0027] Generally, the water circuit 114 may optionally include a reservoir (e.g., a water tank) 118 that fluidly communicates between the separator 120 and the pump 122 via individual fluid conduits. In certain implementations, the reservoir 118 may be coupled to an external water source (e.g., a water pipe, not shown) and receive a supply of water suitable for meeting the demands of the electrochemical stack 200. The connection between the reservoir 118 and the external water source is made outside of the cabinet 104, facilitating connection of the system 100 to an industrial water supply source and, in some cases, reducing the likelihood of damaging equipment within one or more of the first volume 106a, the second volume 106b, or the third volume 106c in the event of a leak in the connection between the external water source and the reservoir 118. It should be understood that the water circuit 114 may include any of a variety of different types of equipment useful for managing the properties of the water flowing through the system 100. By way of example, the water circuit 114 may include filtration or other treatment equipment useful for purifying process water and reducing the concentration of contaminants that may otherwise degrade the performance of other components (e.g., the electrochemical stack 200) over time. Additionally, or alternatively, the water circuit 114 may include a heat exchanger (not shown) that is in thermal communication with one or more of the reservoir 118, the separator 120, or the pump 122 to manage the temperature of each component and / or the temperature of the water flowing through each component.

[0028] The pump 122 may be in fluid communication with the electrochemical stack 200 via a feed conduit 124 that extends from the pump 122 in the first volume 106a to the first fluid connector 110a of the electrochemical module 102. The feed conduit 124 may extend through the wall 105a between the first volume 106a and the second volume 106b. In use, the pump 122 may be powered and move purified water from the reservoir 118 along the feed conduit 124 that extends from the first volume 106a to the second volume 106b and into the electrochemical stack 200 within the second volume 106b. Thus, the pump 122 may be operable to deliver purified water to the second volume 106b while being partitioned from the equipment within each of the second volume 106b and the third volume 106c. Such partitioning of the pump 122 may be advantageous, among other things, to reduce the likelihood that heat generated by the pump 122 during operation can serve as an ignition source for the hydrogen-containing mixture. For example, in the event of a hydrogen leak within the second volume 106b and / or the third volume 106c, a flammable hydrogen-air mixture can inadvertently form within the second volume 106b and / or the third volume 106c. Continuing with this example, keeping the pump 122 partitioned away from the second volume 106b and the third volume 106c can thus reduce the likelihood that ignition can occur before a flammable hydrogen-air mixture is detected and the system can be safely shut down.

[0029] In some implementations, the water circuit 114 may include a recirculation circuit 126 that fluidly communicates between the first fluid connector 110b and the separator 120. Through fluid communication with the first fluid connector 110b, the recirculation circuit 126 may receive an outflow stream consisting essentially of water and oxygen from the anode portion of the electrochemical stack 200. At least a portion of the recirculation circuit 126 extends from the second volume 106b through the wall 105b to the first volume 106a, and the flow of water and oxygen may be directed from the electrochemical stack 200 in the second volume 106b to the separator 120 in the first volume 106a. By transporting oxygen in the first volume 106a to the separator 120 that partitions it from the second volume 106b, the recirculation circuit 126 can reduce the likelihood that oxygen in the excess water flowing from the electrochemical module 102 will inadvertently escape into the second volume 106b and / or the third volume 106c and form a flammable mixture with hydrogen.

[0030] Separator 120 may be any one or more than one of a variety of different types of gas-liquid separators suitable for separating oxygen in the return flow moving from the electrochemical module 102 through the recirculation circuit 126 from the excess water. For example, separator 120 may include a dryer, a condenser, or another device that separates oxygen from the excess water through gravity, with the excess water settling along the bottom portion of separator 120 and the oxygen being collected along the upper portion of separator 120. More generally, separator 120 may operate to separate oxygen from the excess water without using electricity or moving parts that could otherwise act as potential ignition sources within system 100. The oxygen collected by separator 120 may be directed out of the first volume 106a and vented to the environment outside of cabinet 104 or used as a process gas for another part of the factory. By way of example and not limitation, the oxygen collected by separator 120 may be removed from separator 120 using a suction pump or blower. The excess water collected by separator 120 is directed to reservoir 118 and recirculated again through the electrochemical stack 200. That is, more generally, separator 120 may remove oxygen from cabinet 104 at a location remote from the hydrogen-related equipment within the second volume 106b and the third volume 106c while promoting the efficient use of water in hydrogen formation.

[0031] Generally, the hydrogen circuit 116 may collect the hydrogen-containing production stream formed by the electrochemical stack 200 within the second volume 106b and process the production stream using equipment partitioned from the first volume 106a and the second volume 106b. In this context, processing of the production stream may include removing moisture from the production stream and producing substantially pure hydrogen. That is, removing moisture from hydrogen may reduce the potential for the moisture to interfere with one or more downstream processes, and such interference may potentially include degradation of downstream equipment. Further, or alternatively, assuming considerations associated with the safety and energy / hydrogen efficiency of the system 100, processing of the production stream within the hydrogen circuit 116 may require little or no energy while recovering all or substantially all (e.g., greater than about 99 percent) of the hydrogen produced by the electrochemical stack 200.

[0032] In some implementations, the hydrogen circuit 116 may include a product conduit 128 and a dryer 130 that are in fluid communication with each other. More specifically, the product conduit 128 may extend through a wall 105b between the second volume 106b and the third volume 106c. The product conduit 128 may be in fluid communication between an inlet portion 132 of the dryer 130 and the second fluid connector 112 of the electrochemical module 102. Thus, in use, the production stream, which consists essentially of hydrogen and water (e.g., water vapor), may move from the anode side of the electrochemical stack 200, through the second fluid connector 112 and the product conduit 128, to the inlet portion 132 of the dryer 130. The production stream may be at a higher pressure compared to a mixture of oxygen and excess water in the outflow from the anode portion of the electrochemical stack 200 into the recirculation circuit 126. To reduce the likelihood of hydrogen leaking into the third volume 106c, the connections between the product conduit 128 and each of the second fluid connector 112 and the dryer 130 may include gas-tight seals.

[0033] The dryer 130 may be, for example, a pressure swing adsorption (PSA), temperature swing adsorption (TSA) system, or a hybrid PSA-TSA system. The dryer 130 may include one or more layers of a water adsorption material such as activated carbon, silica, zeolite, or alumina. As a product mixture consisting essentially of hydrogen and water moves from the inlet portion 132 to the outlet portion 134 of the dryer 130, at least a portion of the water may be removed from the product mixture through adsorption of either water or hydrogen within the layer of the water adsorption material. When hydrogen is adsorbed, it is removed into the outlet conduit 138 during the pressure and / or temperature swing cycle. When water is adsorbed, it is removed into the pump conduit 140 during the pressure and / or temperature swing cycle. In some cases, the adsorption performed by the dryer 130 may be passive, without the addition of heat or electricity, which could otherwise act as an ignition source for a flammable hydrogen-containing mixture. However, in such cases, considerations related to the backpressure generated by the dryer 130, which is in fluid communication with the electrochemical stack 200, may limit the size and thus the effectiveness of a single pass of the dryer 130 in removing moisture from the product stream.

[0034] At least in light of such considerations related to the effectiveness of a single pass through the dryer 130, the hydrogen circuit 116 further includes, or alternatively includes, a hydrogen pump 136 that is in fluid communication between the outlet portion 134 and the inlet portion 132 of the dryer 130, and may recirculate the hydrogen and water product mixture for an additional pass through the dryer 130. For example, the dryer 130 may direct the dried hydrogen from the outlet portion 134 of the dryer 130 towards an outlet conduit that directs the dried hydrogen to a downstream process or a storage location within the environment outside the cabinet 104. Further, or alternatively, the dryer 130 may direct a portion of the production stream that is not properly dried from the outlet portion 134 of the dryer 130 towards a pump conduit 140 that is in fluid communication with the hydrogen pump 136. In certain cases, at least a portion of the water in the product mixture that travels along the pump conduit 140 may be condensed out of the product mixture and collected within a moisture trap 142 that is in fluid communication with the pump conduit 140 before reaching the hydrogen pump 136. Such moisture condensed within the moisture trap 142 may be collected and / or directed to the environment outside the cabinet 104.

[0035] The hydrogen pump 136 may be, for example, an electrochemical pump. As used in this context, an electrochemical pump is understood to include a proton exchange membrane (i.e., a PEM electrolyte) disposed between an anode and a cathode. The hydrogen pump 136 may generate protons that are movable from the anode through the proton exchange membrane to the cathode and may form pressurized hydrogen. Thus, such an electrochemical pump may be useful, in particular, for recirculating hydrogen within the hydrogen circuit 116 in order to separate hydrogen from water in the mixture while the electrochemical pumping provided by the electrochemical pump is delivered to the hydrogen pump 136 via the pump conduit 140, and also to pressurize the separated hydrogen and facilitate the movement of the pressurized hydrogen to the inlet portion 132 of the dryer 130.

[0036] Alternatively, the hydrogen pump 136 may comprise another hydrogen pumping and / or separation device, such as a diaphragm compressor or blower or a metal-hydride separator (e.g., that selectively adsorbs hydrogen), which may be used in combination with, or instead of, the electrochemical hydrogen pump. In one embodiment, multiple stages of hydrogen pumping and / or recompression may be used. Each stage may comprise one or more than one of a diaphragm compressor or blower, an electrochemical pump, or a metal-hydride separator. In one implementation, the stages may be in a cascaded (i.e., series) configuration and / or may be located within separate enclosures.

[0037] In one implementation, the hydrogen pump 136 may be in fluid communication with a moisture trap 142, and water separated from the hydrogen within the hydrogen pump 136 may be collected and / or directed to the environment outside of the cabinet 104. Additionally or alternatively, the pressurized hydrogen formed by the hydrogen pump 136 may be in fluid communication (e.g., via mixing with the product stream within the product conduit 128) between the hydrogen pump 136 and the inlet portion 132 of the dryer 130, directed along a recovery circuit 144 to recirculate the pressurized hydrogen back to the dryer 130. Among other advantages, recirculating the pressurized hydrogen through the dryer 130 in this manner facilitates moving the hydrogen out of the cabinet 104 through only a single conduit (e.g., the outlet conduit 138), which may reduce potential failure modes compared to the use of multiple outlet points.

[0038] In some implementations, separate ventilation and / or forced convection within each of the first volume 106a, the second volume 106b, and the third volume 106c can be useful for reducing the likelihood of forming a flammable hydrogen-containing mixture within the individual volumes. Additionally or alternatively, forced convection can facilitate control of the temperature within the enclosed environments of the first volume 106a, the second volume 106b, and the third volume 106c. Such temperature control can be useful, for example, for reducing the likelihood that equipment within each individual volume can become a source of ignition and / or fail prematurely.

[0039] Accordingly, system 100 may include a plurality of gas movers 146a, b, c (collectively, the plurality of gas movers 146a, b, c, individually, referred to as gas mover 146a, gas mover 146b, and gas mover 146c). The plurality of gas movers 146a, b, c may include any one or more than one of various different types of fans (e.g., purge fans), blowers, or compressors, unless otherwise specified or apparent from the context. In one implementation, the circuits powered to each of the plurality of gas movers 146a, b, c may be rated for Class 1 Division 2 operation as defined in Articles 500 - 503 of the National Electrical Code (R) (NEC) by the National Fire Protection Association (NFPA) 70(R) (2020), the entire contents of which are incorporated herein by reference. In such an implementation, each of the plurality of gas movers 146a, b, c may be disposed within cabinet 104. Alternatively, each of the plurality of gas movers 146a, b, c may be mounted externally to the outside of cabinet 104 (e.g., on the roof or sidewall of the cabinet), reducing the potential that heat or a spark can act as an inadvertent source of ignition for the contents of the first volume 106a, the second volume 106b, or the third volume 106c.

[0040] Generally, gas mover 146a may be in fluid communication with the first volume 106a, gas mover 146b may be in fluid communication with the second volume 106b, and gas mover 146c may be in fluid communication with the third volume 106c. For example, each of the plurality of gas movers 146a, b, c may be in fluid communication between the environment outside the cabinet 104 and the corresponding one of the first volume 106a, the second volume 106b, and the third volume 106c, and may be configured to ventilate the individual volumes of the cabinet 104 separately. Additionally, or alternatively, each of the plurality of gas movers 146a, b, c may be operable to form a negative pressure within the corresponding one of the first volume 106a, the second volume 106b, and the third volume 106c with respect to the environment outside the cabinet 104. Such a negative pressure may, for example, draw air from the environment into the first volume 106a, the second volume 106b, and the third volume 106c, and any hydrogen leakage into the first volume 106a, the second volume 106b, or the third volume 106c is useful to reduce the likelihood that it can accumulate at a concentration above the lower flammability limit of the hydrogen-air mixture at the temperature and pressure associated with the cabinet 104. Further, or alternatively, the negative pressure within the first volume 106a, the second volume 106b, and the third volume 106c may reduce the likelihood that a flammable hydrogen-containing mixture can escape from the cabinet 104. In certain cases, the cabinet 104 may be insulated to facilitate maintaining one or more components within the first volume 106a, the second volume 106b, and the third volume 106c within a temperature range suitable for operation of the electrochemical stack 200 (e.g., from about 60°C to about 80°C).

[0041] The plurality of gas movers 146a, b, c may be useful for reducing the likelihood of an unsafe condition formed within the first volume 106a, the second volume 106b, or the third volume 106c, but it should be understood that one or more of these volumes may additionally, or alternatively, include an area classification component. In such cases, the corresponding volume may not need to be ventilated.

[0042] In one implementation, system 100 may include a controller 148 that is in electrical communication with at least one or more components within the first volume 106a, the second volume 106b, or the third volume 106c. Generally, controller 148 may include one or more processors and a non-transitory computer-readable storage medium having instructions stored thereon for controlling, by the one or more processors, one or more of the startup, operation, or shutdown of any one or more of the various aspects of system 100 to facilitate safe and efficient operation. For example, controller 148 may include one or more embedded controllers for one or more components within the first volume 106a, the second volume 106b, or the third volume 106c. Additionally, or alternatively, controller 148 may be in electrical communication with at least the electrochemical stack 200 and the power source 150. Continuing with this example, controller 148 may interrupt power to the electrochemical stack 200 if an abnormal condition is detected. Further, or instead, controller 148 may reduce the likelihood of providing power to the electrochemical stack 200 and igniting a hydrogen-containing mixture within the cabinet 104 after a startup protocol (e.g., purging of the first volume 106a, the second volume 106b, and / or the third volume 106c).

[0043] In some implementations, the cabinet 104 may define a fourth volume 106d, and the controller 148 may be disposed within the fourth volume 106d while wirelessly or wiredly communicating with one or more of the various different components described herein that are disposed within one or more of the first volume 106a, the second volume 106b, or the third volume 106c. The fourth volume 106d is generally located in the vicinity of the first volume 106a, the second volume 106b, and the third volume 106c, and may facilitate electrical connection and / or disconnection as part of one or more of installation, startup, normal operation, maintenance, or repair. Thus, for example, the fourth volume 106d may be disposed along the upper portion of the cabinet 104 and / or along the back portion of the cabinet 104, and both locations may provide useful access to each of the first volume 106a, the second volume 106b, and the third volume 106c while being away from the first door 152a, the second door 152b, and the third door 152c, respectively, which can be used to provide access to the first volume 106a, the second volume 106b, and the third volume 106c. Further, or alternatively, with the controller 148 disposed therein, the fourth volume 106d may be fluidly isolated from each of the first volume 106a, the second volume 106b, and / or the third volume 106c by the roof 105c or the back wall of the cabinet 104, reducing the likelihood of exposure of the controller 148 to one or more process fluids during installation, startup, normal operation, shutdown, maintenance, or repair that could impair the operation of the controller 148.

[0044] The first volume 106a, the second volume 106b, and the third volume 106c were described as having a negative pressure provided by a plurality of gas movers 146a, 146b, and 146c, but the fourth volume 106d is in fluid communication with a fan 154 that is operable to generate a positive pressure within the fourth volume 106d relative to the environment outside the fourth volume 106d and may control the temperature of the controller 148 and / or other components within the fourth volume 106d. Further, or alternatively, although the fourth volume 106d was described as storing the controller 148, the fourth volume 106d may store all control and power electronics equipment for the system 100 such that inadvertent sparking or overheating of one or more of such components reduces the likelihood that hydrogen-containing mixtures within one or more of the first volume 106a, the second volume 106b, or the third volume 106c can be ignited.

[0045] In one implementation, the controller 148 may further or alternatively monitor one or more ambient conditions within the first volume 106a, the second volume 106b, and the third volume 106c and facilitate taking one or more corrective actions before an abnormal condition causes damage to the system 100 and / or an area in the vicinity of the system 100. In particular, assuming potential damage that may be caused by the presence of a flammable hydrogen-containing mixture within the cabinet 104, the system 100 may include a plurality of gas sensors 158a, b, c (collectively, the plurality of gas sensors 158a, b, c; individually, referred to as gas sensor 158a, gas sensor 158b, and gas sensor 158c). Each of the plurality of gas sensors 158a, b, c may include any one or more of various different types of hydrogen sensors such as, but not limited to, optical fiber sensors, electrochemical hydrogen sensors, thin film sensors, and the like. To facilitate robust detection of hydrogen within the cabinet 104, gas sensor 158a may be disposed within the first volume 106a, gas sensor 158b may be disposed within the second volume 106b, and gas sensor 158c may be disposed within the third volume 106c. Each of the plurality of gas sensors 158a, b, c may be calibrated to detect hydrogen concentration levels below the hydrogen flammability limit to facilitate taking corrective actions before a fire event can occur. For this purpose, the controller 148 may be in electrical communication with each of the plurality of gas sensors 158a, b, c, and the non-transitory computer-readable storage medium of the controller 148 may store thereon instructions for causing one or more processors of the controller 148 to interrupt electrical communication between the power supply 150 and the equipment within the cabinet 104 based on signals received from one or more of the plurality of gas sensors 158a, b, c that indicate a dangerous hydrogen concentration. Additionally or alternatively, a signal received from one or more of the plurality of gas sensors 158a, b, c may indicate a rapid increase in hydrogen concentration.

[0046] The controller 148 may be useful for taking corrective measures against potentially harmful conditions within the cabinet 104, but the system 100 may also, additionally or alternatively, include one or more safety features useful for mitigating damage to the system 100 and / or the vicinity of the system in the event of an explosion. For example, the system 100 may include a pressure relief valve 160 that is in fluid communication with at least a third volume 106c of the cabinet 104. The pressure relief valve 160 may be a mechanical valve that self-opens at a predetermined threshold pressure within the third volume 106c. In some instances, the predetermined threshold pressure may be a pressure increase resulting from a leak of pressurized hydrogen into the third volume 106c. Alternatively, the predetermined threshold pressure may be a high pressure associated with a rapid pressure rise associated with the combustion of a hydrogen-containing mixture. In either case, the pressure relief valve 160 may vent the contents of the third volume 106c to the environment and mitigate damage that might otherwise occur.

[0047] Generally, components within cabinet 104 may be connectable to external resources from locations outside cabinet 104 along one or more surfaces of cabinet 104. Such connections may facilitate the deployment of system 100 without the need for personnel to open cabinet 104. Additionally or alternatively, connections made outside cabinet 104 may provide additional spacing between components within each of the first volume 106a, the second volume 106b, and the third volume 106c, as compared to otherwise comparable arrangements. This may in turn be useful for providing better access to components within cabinet 104 to trained personnel. Additionally or alternatively, connecting components along one or more outer surfaces of cabinet 104 may provide safety advantages. For example, electrical contacts 156 may be disposed on the outer surface of cabinet 104 (e.g., along the outer surface of cabinet 104 that defines the fourth volume 106d), and electrical contacts 156 may be in electrical communication with at least the electrochemical stack 200 via the controller 148. Continuing with this example, electrical contacts 156 may be releasably engagable while in electrical communication with a power source 150 located outside cabinet 104 (e.g., via a contact or fuse). If the disconnection function causes a spark, the spark will be located outside cabinet 104 and generally away from a potentially flammable hydrogen-containing gas mixture that could inadvertently form within the first volume 106a, the second volume 106b, and / or the third volume 106c.

[0048] Since an aspect of the overall layout of system 100 useful for safely producing hydrogen in a small footprint has been described, attention is now directed to specific features of the electrochemical module 102 itself that may separately manage water and gas within the electrochemical module 102, provide additional or alternative safety during operation of system 100, and / or facilitate the deployment, maintenance, and / or repair of system 100, and thus may facilitate reducing the downtime associated with such events.

[0049] Referring now to FIGS. 2A-2C, the electrochemical stack 200 may include a first membrane electrode assembly (MEA) 201, a second membrane electrode assembly (MEA) 202, and a bipolar plate 204 that collectively define two complete electrochemical cells for the generation of hydrogen. The electrochemical stack 200 may also include a first end plate 206 and a second end plate 208 that sandwich the first MEA 201, the second MEA 202, and the bipolar plate 204 in contact with each other and may direct fluid flow into and out of the electrochemical stack 200. The electrochemical stack 200 is described as including two complete cells, i.e., a single bipolar plate and two MEAs, but it should be understood that this is for clarity of explanation and illustration only. More generally, the electrochemical stack 200 may include any number of MEAs and bipolar plates useful for meeting the hydrogen generation requirements of the system 100 shown in FIGS. 1A and 1B while maintaining the separation between pressurized hydrogen and the lower pressure water and oxygen flowing through the electrochemical stack 200. That is, unless otherwise specified or apparent from the context, the electrochemical stack 200 may include more than one bipolar plate, a single MEA, and / or more than two MEAs. Further, or alternatively, the electrochemical stack 200 is shown as including a first end plate 206 in contact with the first MEA 201 and a second end plate 208 in contact with the second MEA 202, but it should be understood that this is again for purposes of clarity and efficient explanation. That is, in some instances, the bipolar plate 204 may be disposed between the first end plate 206 and the first MEA 201 and / or between the second end plate 208 and the second MEA 202 without departing from the scope of the present disclosure.

[0050] Generally, the first MEA 201 and the second MEA 202 may be the same as each other. For example, the first MEA 201 may include an anode 210a, a cathode 212a, and a proton exchange membrane (e.g., PEM electrolyte) 214a therebetween. Similarly, the second MEA 202 may include an anode 210b, a cathode 212b, and a proton exchange membrane 214b therebetween. Each of the anodes 210a, 210b may include an anode catalyst (i.e., an electrode) in contact with the membrane and an optional anode fluid diffusion layer. Each of the cathodes 212a, 212b may include a cathode catalyst (i.e., an electrode) in contact with the membrane and an optional cathode gas diffusion layer. The anode electrode may include any suitable anode catalyst such as an iridium layer. The anode fluid diffusion layer 246 may include a porous material such as a porous titanium sheet or a porous carbon sheet, a mesh, or a fabric. The cathode electrode may include any suitable cathode catalyst such as a platinum layer. The cathode gas diffusion layer may include porous carbon. Other noble metal catalyst layers may also be used for the anode and / or cathode electrodes. The electrolyte may be any suitable proton exchange (e.g., hydrogen ion transport) polymer membrane such as a Nafion(R) membrane made of a sulfonated tetrafluoroethylene-based fluoropolymer-copolymer having the formula C7HF 13 O5S·C2F4.

[0051] The bipolar plate 204 may be disposed between the cathode 212a of the first MEA 201 and the anode 210b of the second MEA 202. Generally, the bipolar plate 204 may include a substrate 222, an anode gasket 224, and a cathode gasket 226. The substrate 222 has an anode (i.e., water) side 228 and a cathode (i.e., hydrogen) side 230 that face each other. The anode gasket 224 may be fixed to the anode side 228 of the substrate 222, and the cathode gasket 226 may be fixed to the cathode side 230 of the substrate 222. Such a fixed positioning of the anode gasket 224 and the cathode gasket 226 on opposite sides of the substrate 222 may facilitate the formation of two seals that are consistent with each other and with the first MEA 201 and the second MEA 202 on both sides of the bipolar plate 204. The gaskets form a double seal around the active areas (i.e., the anode (e.g., water) flow field 234 and the cathode (e.g., hydrogen) flow field 240) located on the individual opposite sides 228, 230 of the bipolar plate 204. Further, or alternatively, in cases where the electrochemical stack includes an MEA case between two cases of the bipolar plate 204, the anode gasket 224 and the cathode gasket 226 may form a double seal along the active area of the MEA. Thus, more generally, the anode gasket 224 and the cathode gasket 226 form a sealing engagement with one or more MEAs in the electrochemical stack, isolate the flow within the electrode stack, and thus reduce the likelihood that pressurized hydrogen will inadvertently mix with the flow of water and oxygen exiting the electrochemical stack and generate a flammable hydrogen-oxygen mixture within the system 100 shown in FIGS. 1A and 1B.

[0052] The substrate 222 may be formed from any one or more of a variety of different types of materials that are conductive, thermally conductive, and have a suitable strength to withstand the high pressure of hydrogen flowing along the cathode side 230 of the substrate 222 during use. Thus, for example, the substrate 222 may be formed, at least in part, from one or more of plasticized graphite or carbon composites. Additionally, or alternatively, the substrate 222 may advantageously be formed from one or more materials suitable for withstanding long-term exposure to water on the anode side 228 of the substrate 222. Thus, in some instances, the anode side 228 of the substrate 222 may include an oxidation inhibitor coating that is conductive, and embodiments thereof include titanium, titanium oxide, titanium nitride, or combinations thereof. The oxidation inhibitor may generally extend along at least those portions of the anode side 228 of the substrate 222 that are exposed to water during operation of the electrochemical stack 200. That is, the oxidation inhibitor may extend along at least the anode flow field 234 inside the anode gasket 224 on the anode side 228 of the substrate 222. In some implementations, the oxide inhibitor may extend along a plurality of anode ports (i.e., water riser openings) 232 that extend from the anode side 228 to the cathode side 230 of the substrate 222. The oxidation inhibitor may also be located within the anode plenum 235, which connects the anode portion 232 to the anode flow field 234 on the anode side of the substrate 222.

[0053] The cathode ring seal 237 may be positioned around each cathode port (i.e., hydrogen riser opening) 238 on the anode side 228 of the substrate, as shown in FIG. 2B. The cathode ring seal 237 prevents hydrogen from leaking into the anode flow field 234 on the anode side 228 of the substrate 222. In contrast, the anode ring seal 233 may be positioned around each one or more anode ports 232 on the cathode side 230 of the substrate 222. For example, as shown in FIG. 2C, two anode ports 232 are surrounded by a common anode ring seal 233 to prevent water from flowing into the cathode flow field 240 on the cathode side of the substrate 222.

[0054] The anode flow field 234 includes a plurality of straight and / or curved ribs 235 separated by flow channels 236 that are oriented to direct a liquid (e.g., purified water) between at least some of the plurality of anode ports 232 so as to be useful for uniformly dispersing the purified water along the anode 210b of the second MEA 202 in the configuration shown in FIG. 2A. The anode gasket 224 may surround the anode flow field 234 and the plurality of anode ports 232 along the anode side 228 of the substrate 222 and limit the movement of the purified water moving along the anode 210b. That is, the anode side 228 of the substrate 222 may be seal-engaged with the anode 210b of the second MEA 202 via the anode gasket 224 such that the anode channels 236 are positioned therebetween. The liquid provided from the first fluid connector 110a under pressure, provided by a source external to the electrochemical stack 200 (e.g., a pump 122 of the water circuit 114 shown in FIG. 1B), flows along the anode channels 236 and is directed across the anode 210b of the second MEA 202 from one instance of the plurality of anode ports 232 to another instance of the plurality of anode ports 232, and the liquid (e.g., remaining water and oxygen) may be directed out of the electrochemical stack 200 through another first fluid connector 110b.

[0055] In addition, the substrate 222 may include a plurality of cathode ports (i.e., hydrogen riser openings) 238 each extending from the anode side 228 to the cathode side 230 of the substrate 222. The cathode side 230 of the substrate 222 may include a cathode flow field 240. The cathode flow field 240 is formed along the cathode 212a of the first MEA 201 in the configuration shown in FIG. 2A and includes a plurality of straight and / or curved ribs 241 separated by cathode flow channels 242 that are oriented to direct a pressurized gas (e.g., hydrogen) toward the plurality of cathode ports 238 so as to be useful for directing the pressurized hydrogen. A cathode plenum 239 may be located between the individual cathode ports 238 and the cathode flow field 240. The cathode gasket 226 may surround the cathode flow field 240, the cathode plenum 239, and the plurality of cathode ports 238 along the cathode side 230 of the substrate 222 and may limit the movement of the pressurized hydrogen along the cathode 212a. For example, the cathode side 230 of the substrate 222 may be sealingly engaged with the cathode 212a of the first MEA 201 via the cathode gasket 226 such that the cathode flow channels 242 are defined between the cathode 212a of the first MEA 201 and the cathode side 230 of the substrate 222. The pressure of the hydrogen formed along the cathode 212a may move the hydrogen toward the cathode ports 238 located on the diagonal opposite the cathode inlet port along at least a portion of the cathode channels 242. The pressurized hydrogen may flow out of the cathode ports 238 and out of the electrochemical stack 200 through the second fluid connector 112 and may be processed by the hydrogen circuit 116 as shown in FIG. 1B.

[0056] The anode gasket 224 on the anode side 228 of the substrate 222 and the cathode gasket 226 on the cathode side 230 of the substrate 222 may have different shapes (as shown in FIGS. 2B and 2C). For example, the anode gasket 224 may extend between a plurality of anode ports 232 and a plurality of cathode ports 238 on the anode side 228 of the substrate 222. In other words, the anode gasket 224 surrounds the anode ports 232 and the anode flow field 234 on one lateral side, but leaves the cathode portion 238 outside the surrounded area. In the arranged position, thus, the anode gasket 224 can fluidically isolate the anode flow from the cathode flow.

[0057] In contrast, the cathode gasket 226 on the cathode side 230 of the substrate 222 does not extend between the plurality of anode ports 232 and the plurality of cathode ports 238. In other words, the cathode gasket 226 surrounds the anode ports 232, the cathode portion 238, and the cathode flow field 240. Instead, the anode ring seal 233 isolates the anode portion 232 from the cathode ports 238 and the cathode flow field 240 on the cathode side 230 of the substrate 222.

[0058] In one configuration, the anode flow field 234 and the cathode flow field 240 may have the same shape and provide the same active area along the first MEA 201 and the second MEA 202, even though they are on opposite sides of the substrate 222. Thus, overall, it should be understood that the difference in shape between the anode gasket 224 and the cathode gasket 226, along with the positioning of the anode ring seal and the same shape of the anode flow field 234 and the cathode flow field 240, can result in different sealed areas. These different sealed areas are complementary to each other and fluidically isolate the lower-pressure flow of purified water along the anode channels 236 from the pressurized hydrogen flowing along the cathode channels 242, while still allowing each flow to move through the electrochemical stack 200 and ultimately exit the electrochemical stack 200 along different channels, facilitating this.

[0059] In one implementation, the cathode flow field 240 may be shaped such that the minimum bounding rectangle of the cathode flow field 240 is square. As used in this context, the term "minimum bounding rectangle" is to be understood as the smallest rectangle defined by the maximum x and y dimensions of the cathode flow field 240. The plurality of cathode ports 238 may include two cathode ports per substrate 222, which are located within opposite corners of the diagonal with respect to the minimum bounding rectangle (e.g., within the minimum bounding rectangle). The other two opposite corners of the diagonal are devoid of the cathode ports 238. In cases where the minimum bounding rectangle is square, the diagonal positioning of the cathode ports 238 with respect to the minimum bounding rectangle can promote the diagonal flow of pressurized hydrogen along the entire cathode flow field 240, leaving a large margin of the material of the substrate 222 for strength against the contained internal hydrogen pressure. Alternatively, the substrate 222 may be rectangular. The plurality of cathode ports 238 are positioned away from the edges of the substrate 222 such that each of the plurality of cathode ports 238 is well-reinforced by the material of the substrate 222 between the individual one of the plurality of cathode ports 238 and the closest edge of the substrate 222.

[0060] Assuming a large pressure difference between the flow of pressurized hydrogen along the cathode channel 242 and the flow of water and oxygen along the anode channel 236, the electrochemical stack 200 may include an anode fluid diffusion layer disposed within the anode channel 236 and optionally between the anode electrode of the anode 210b of the second MEA 202 and the anode side 228 of the substrate 222 (e.g., the anode rib 235). The porous material of the anode fluid diffusion layer 246 generally provides structural support on the anode side 228 of the substrate 222 and allows the flow of water and oxygen through the anode channel 236 without a substantial increase in flow restriction through the anode channel 236 while resisting crushing that may result from the pressure difference on the opposite side of the substrate 222. For purposes of illustration, the porous material 246 is shown along only one anode channel 236. However, it should be understood that in some implementations, the porous material 246 may be disposed inside all of the anode channels 236.

[0061] As an additional or alternative safety measure, the electrochemical stack 200 may include a housing 248 disposed about the first MEA 201, the second MEA 202, the bipolar plate 204, the first end plate 206, and the second end plate 208, as shown in FIG. 2A. More specifically, the housing 248 may be formed from one or more materials useful for absorbing the force of one or more materials that may be ejected in the event of a failure event (e.g., a failure resulting from a failure under the force of pressurized hydrogen and / or an explosion of a hydrogen-containing mixture due to carelessness). By way of example, the housing 248 may include one or more of metal or aramid (e.g., Kevlar(R)) fibers.

[0062] Since various features of the electrochemical stack 200 have been described, attention is now directed to the operation of the electrochemical stack 200 that uses water and electricity as inputs to form pressurized hydrogen. In particular, as shown in FIG. 2A, an electric field E (i.e., voltage) may be applied across the electrochemical stack 200 (i.e., between the end plates 206 and 208) from the power supply 150 shown in FIG. 1B. The bipolar plate 204 may be fluidly isolated and maintained from the lower pressure water and oxygen, except for the proton exchange that occurs in the first MEA 201 and the second MEA 202 and through the proton exchange membranes 214a and 214b, to form a flow of pressurized hydrogen. The first MEA 201 and the second MEA 202 may be electrically connected to each other in series.

[0063] Purified water (e.g., from the water circuit 114 shown in FIG. 1B) may be introduced into the electrochemical stack 200 through the first fluid connector 110a of the electrochemical module 102 as shown in FIG. 1B. Inside the electrochemical stack 200, the purified water may flow along the intake channel 216 that extends through, among other components, the bipolar plate 204, and may direct the purified water towards the anode 210a of the first MEA 201 and the anode 210b of the second MEA 202. By using the electric field E applied across the anode 210a and the cathode 212a of the first MEA 201, the purified water may decompose along the anode 210a into protons (H + ) and oxygen. The protons (H + ) may move from the anode 210a to the cathode 212a through the proton exchange membrane 214a. At the cathode 212a, the protons (H +) can be combined with each other to form pressurized hydrogen along the cathode 212a. Through a similar process, pressurized hydrogen may also be formed along the cathode 212b of the second MEA 202. The flow of pressurized hydrogen formed by each of the first MEA 201 and the second MEA 202 is combined with each other and flows out of the electrochemical stack 200 through two hydrogen exhaust channels 218 that extend, among other components, through the bipolar plate 204. Finally, the pressurized hydrogen can be directed out of the second fluid connector 112 of the electrochemical module 102 for processing (as shown in FIG. 1B and discussed above) towards the hydrogen circuit 116. The flow of oxygen and water along the anodes 210a and 210b is combined with each other and flows out of the electrochemical stack 200 through the outlet anode port 232 and the outlet channel 220 that extend, among other components, through the end plate 206. The main flow of water and oxygen can be directed out of the first fluid connector 110b of the electrochemical module 102 for processing (as shown in FIG. 1B and discussed above) towards the water circuit 114.

[0064] As discussed above, bipolar plate 204 is in sealing engagement with cathode 212a of the first MEA 201 and anode 210b of the second MEA, and can facilitate keeping pressurized hydrogen formed along cathode 212a of the first MEA 201 separate from water and oxygen flowing along anode 210b of the second MEA 202. This separation is useful for reducing the likelihood of leakage of pressurized hydrogen from the electrochemical stack 200 and thus, through electrolysis, for safely producing industrial-scale amounts of hydrogen, in addition to, or instead of, any one or more aspects of the modularity of the system 100 (shown in FIGS. 1A and 1B), can be useful. Additionally, or alternatively, as described in more detail with respect to FIGS. 3A and 3B below, the sealed engagement facilitated by bipolar plate 204 can facilitate removal of the electrochemical module 102 with a lower likelihood of water overflow in the vicinity of the cabinet 104 shown in FIG. 1A (e.g., for repairing, servicing, and / or replacing the electrochemical stack 200).

[0065] Referring now to FIGS. 3A and 3B, the electrochemical module 102 may include a liquid management section 302 and a gas management section 304 that are releasably securable to each other along an interface 305 (e.g., using clamps, bolts, or combinations thereof) to facilitate deployment, servicing, and / or repair. For example, the gas management section 304 may be removable from the liquid management section 302 without having to disconnect the water connections at the first fluid connectors 110a, b. The ability to remove the gas management section 304 from the liquid management section 302 can reduce the time required to perform mechanical operations associated with deployment, servicing, and / or repair as compared to a deployment that requires removal of the water connections. Further, or alternatively, the water connections can remain intact, so inadvertent dispersion of water around the cabinet 104 shown in FIG. 1A is less likely.

[0066] Generally, the liquid management section 302 may include a plurality of first fluid connectors 110a, b that are fluidly connected to the individual inlet and outlet water manifolds 306a, b. Each of the plurality of first fluid connectors 110a, b may be in fluid communication with the individual manifolds 306a, b. Consequently, the manifolds 306a, b are attachable to the gas management section 304 and deliver purified water to the gas management section 304 via the first fluid connector 110a and the liquid connection 310a, and receive the anode effluent of water and oxygen via the first fluid connector 110b and the liquid connection 310b (e.g., O-rings and / or tubes), and may include individual liquid connections 310a, 310b. The manifolds 306a, b may comprise hollow plastic or metal boxes. The liquid management section 302 may include a support such as a leg 308 or pedestal-type support.

[0067] An optional separator plate 309, such as a stainless steel plate, may be located on top of the liquid management section 302 such that the individual liquid connections 310a, 310b extend through the separator plate. For example, the individual liquid connections 310a, 310b may have holes within a separator plate 309 that are surrounded by individual O-rings.

[0068] Referring now to FIGS. 2A and 3A and 3B, the gas management section 304 of the electrochemical module 102 may include the electrochemical stack 200, a collector plate 312, and a second fluid connector 112. Thus, in other words, while the liquid management section 302 and the gas management section 304 may be separable from each other along the low-pressure water connections 110a, b, the high-pressure connection 112, which is associated with the flow of pressurized hydrogen external to the electrochemical module 102, need not be disrupted, and thus, the failure modes associated with repeatedly disconnecting and re-establishing the high-pressure connection do not exist within the electrochemical module 102. The collector plate 312 may be oriented perpendicular to the direction of the connectors 110a, b and 112 (e.g., out of the page in FIG. 3A).

[0069] The above-described systems, devices, methods, processes, and equivalents may be implemented in hardware, software, or any combination thereof suitable for control, data access, and data processing as described herein. The hardware may include general-purpose computers and / or dedicated computing devices. This may include implementation within one or more microprocessors, microcontrollers, embedded microcontrollers, programmable digital signal processors, or other programmable devices or processing circuits, along with internal and / or external memory. This may also include, or alternatively, one or more application-specific integrated circuits, programmable gate arrays, programmable array logic components, or any other devices or devices that may be configured to process electronic signals. Further, the realization of the processes or devices described above may include computer-executable code that is stored, compiled, or interpreted and executed on one of the aforementioned devices, as well as on a heterogeneous combination of processors, processor architectures, or different combinations of hardware and software, using a structured programming language such as C, an object-oriented programming language such as C++, or any other high-level or low-level programming language (including assembly language, hardware description language, and database programming languages and techniques). At the same time, the processing may be distributed across the various systems and other devices described above, or all functionality may be integrated within a dedicated stand-alone device. All such permutations and combinations are intended to be within the scope of the present disclosure.

[0070] Embodiments disclosed herein may include a computer program product comprising computer-executable code or computer-usable code that, when executed on one or more computing devices, performs any and / or all of the steps of the control system described above. The code may be stored in a computer memory in a non-transitory manner, which may be the memory in which the program executes (such as random access memory associated with a processor), or a storage device such as a disk drive, flash memory, or any other optical, electromagnetic, magnetic, infrared, or other device or combination of devices. In another aspect, any of the control systems described above may be embodied in any suitable transmission or propagation medium that conveys computer-executable code and / or any input thereto or output therefrom.

[0071] The method steps of the implementations described herein are intended to include any suitable method of carrying out such method steps in a manner consistent with the patentability of the following claims, unless a different meaning is explicitly provided or otherwise apparent from the context. Thus, for example, performing step X may include any suitable method of causing another party, such as a remote user, remote processing resource (such as a server or cloud computer), or machine, to perform step X. Similarly, performing steps X, Y, and Z may include any method of instructing or controlling any combination of such other individuals or resources to perform steps X, Y, and Z and obtain the benefits of such steps. Thus, the method steps of the implementations described herein are intended to include any suitable method of causing one or more other parties or entities to perform steps in a manner consistent with the patentability of the following claims, unless a different meaning is explicitly provided or otherwise apparent from the context. Such parties or entities need not be under the instruction or control of any other party or entity and need not be located within a particular jurisdiction.

[0072] It should be understood that the devices, systems, and methods described above are presented by way of example and not limitation. Numerous variations, additions, omissions, and other modifications will be apparent to those skilled in the art. Additionally, the order or presentation of method steps in the above description and drawings is not intended to require the order in which the recited steps are performed, unless a particular order is explicitly required or otherwise apparent from the context. Accordingly, while particular embodiments have been illustrated and described, it will be apparent to those skilled in the art that various changes and modifications in form and detail may be made therein without departing from the scope of the present disclosure.

Claims

1. A system for hydrogen generation, comprising: at least one cabinet defining a first volume, a second volume, and a third volume, wherein the first volume, the second volume, and the third volume are fluidly isolated from each other; at least one cabinet; a water circuit located within the first volume; an electrochemical module comprising an electrolytic cell electrochemical stack located within the second volume; a hydrogen circuit located within the third volume; at least one first fluid connector fluidly connecting the water circuit and the electrolytic cell electrochemical stack; at least one second fluid connector fluidly connecting the electrolytic cell electrochemical stack and the hydrogen circuit A system comprising:

2. The at least one cabinet comprises a single cabinet, within which the first volume is isolated from the second volume by a first inner wall, and the second volume is isolated from the third volume by a second inner wall. The at least one first fluid connector extends through the first inner wall. The at least one second fluid connector extends through the second inner wall. The system according to claim 1.

3. A first gas mover configured to be fluidly connected to the first volume but not to the second or third volume, and to ventilate the first volume without ventilating the second or third volume. A first gas mover; A second gas mover configured to be fluidly connected to the second volume but not to the first or third volume, and to ventilate the second volume without ventilating the first or third volume. A second gas mover; A third gas mover, the third gas mover being fluidly connected to the third volume but not connected to the first or the second volume and configured to ventilate the third volume without ventilating the first or the second volume, a third gas mover The system according to claim 1, further comprising . **Claim 4** The system according to claim 3, wherein the first, second, and third gas movers are operable to create a negative pressure within each of the first volume, the second volume, and the third volume with respect to the environment outside the single cabinet. **Claim 5** The electrolytic cell electrochemical stack includes at least one bipolar plate and a plurality of membrane electrode assemblies (MEAs), the plurality of MEAs and the at least one bipolar plate define at least one anode channel and at least one cathode channel separated from each other by the at least one bipolar plate, the at least one anode channel is in fluid communication with the water circuit via the at least one first fluid connector, the at least one cathode channel is in fluid communication with the hydrogen circuit via the second fluid connector, the MEA includes an anode, a cathode, and a proton exchange membrane therebetween, The system according to claim 1, wherein the second volume is located between the first volume and the third volume. **Claim 6** The water circuit includes a pump, a reservoir, and a separator, the at least one first fluid connector includes two fluid connectors, the reservoir is in fluid communication between the separator and the pump, the pump is in fluid communication with the anode channel of the electrochemical stack via one of the two first fluid connectors, The system according to claim 5, wherein the separator is in fluid communication with the at least one anode channel of the electrochemical stack via a second one of the two first fluid connectors.

7. The hydrogen circuit a dryer having an inlet portion in fluid communication with the at least one cathode channel of the electrolytic cell electrochemical stack via the second fluid connector, and a hydrogen pump in fluid communication with the outlet and inlet portions of the dryer, the hydrogen pump being operable to recirculate pressurized hydrogen from the outlet portion of the dryer to the inlet portion of the dryer. The system according to claim 5, comprising

8. a controller located within a fourth volume of the cabinet that is in electrical communication with the electrochemical stack and fluidly isolated from each of the first volume, the second volume, and the third volume, and an electrical contact disposed on an outer surface of the at least one cabinet, the electrical contact being releasably engageable while in electrical communication with a power source, and the electrical contact being in electrical communication with the electrochemical stack via the controller. The system according to claim 4, further comprising

9. The system according to claim 8, further comprising a fan in fluid communication with the fourth volume, the fan being operable to create a positive pressure within the fourth volume with respect to the environment outside the cabinet.

10. further comprising a plurality of gas sensors, each of the plurality of gas sensors being configured to measure a hydrogen-containing gas, each gas sensor being disposed within one of the first volume, the second volume, and the third volume, Each gas sensor is in electrical communication with the controller, The controller is configured to interrupt electrical communication between the power supply and the equipment in the cabinet based on a signal received from one or more of the plurality of gas sensors, the system of claim 8.

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